1) Field of the Invention:
This invention relates to novel cephem derivatives useful as antibacterial agents.
2) Description of the Related Art:
Many cephem derivatives having a 2-(5-amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetamido group at the 7-position and a quaternary ammoniomethyl group at the 3-position have been known to date. For example, see Japanese Patent Application Laid-Open Nos. 4789/1983, 130295/1984 and 97983/1985, European Patent Publication No. 188255 A2, etc.